1. Field of the Invention
The present invention relates to covers for swimming pools and fish ponds and similar water pools and, in particular, to a cover which permits drainage of water from the upper surface of the cover via a drain and the filtering out of particulate contaminants in the drained water with a filter media selectively and removably positionable in alignment with the drain without removal of the cover.
2. Description of the Prior Art
While the present invention relates to swimming pools, fish ponds and similar water pools, the description which follows will be directed towards swimming pools with the understanding that the application may be made for similar fish pools or other similar water pools.
Covers for swimming pools are frequently required to prevent the ingress of dirt or waste material, such as fallen leaves, into the pool during the off season when the pool is not in use. The cover also serves to prevent or reduce evaporation of water and to further reduce thermal losses from the water particularly, again, in the off season when the pool is not in use.
Covers of flexible waterproof sheet material are the preferred method of covering a swimming pool, the cover extending beyond the periphery of the pool where it is secured. Covers of this type have the disadvantage in that they sag in their unsupported areas, normally the midpoint of the pool and therefore they tend to collect rain water, melted snow and other accumulated dirt, leaves, and debris during the period when the cover is in position. The pool owner must physically remove the particulate dirt, waste and debris from the cover and drain the accumulated water in order to prevent the bursting of the cover under the weight.
A partial solution to the problem was taught in U.S. Pat. No. 3,184,764 to West wherein a drain plug was positioned at the midpoint of the cover, which would coincide with the lowest point of the sag of the cover during the off season when the cover was in position. Over this drain, was positioned a mesh screen for the purpose of retaining leaves, paper, and other debris of a coarse or large nature. This allowed the accumulated water, either from rain or melted snow, to pass through the mesh, and through the drain hole and into the pool thereby alleviating the excess weight on the cover and preventing the bursting or tearing of the cover.
While the mesh screen of the '764 patent prevented coarse debris from entering into the pool, nevertheless, particulate matter, such as dirt or decaying leaf particulate, could pass through the mesh and through the drain hole into the pool presenting a cleaning problem in the springtime when the pool cover was removed.
U.S. Pat. No. 4,233,695 to Rowney attempted to present an answer to this problem by having a pocket formed over a mesh drain in the cover with the pocket having at least one aperture allowing water to pass through the aperture, and through the mesh drain. Positioned in the pocket between the aperture and the mesh drain would be a filter media in the form of a pad of a fibrous nature which would collect the particulate matter which might not have been trapped by the mesh screen as taught in the '764 patent.
The drawback to the solution proposed by Rowney in the '695 patent is that the filter media proposed by Rowney is fixed and thus can become impregnated with particulate matter to the point where it, in effect, plugs the drainage of the water or melting snow from the cover thereby preventing its drainage and increasing the weight and burden on the swimming pool cover. The pool owner's only solution in this situation is to remove the cover and replace the filter pad.
One of the most recent developments in an attempt to solve these problems is U.S. Pat. No. 5,259,078 to Crandall in which pockets are formed on the underside of the pool cover, and the pockets are lined with a filter material such that water is allowed to pass through the pool cover through a mesh opening in the pool cover, enter the pocket and pass through the filter material and into the pool. The pocket accumulates particulate matter as a result of the filter media lining. While this structure may eliminate the passage of small debris and particulate matter into the pool, it too cannot be cleaned or removed until the pool cover is removed as admitted by the inventor. Therefore, the possibility of the filter media becoming plugged and preventing the passage of water through the filter media into the pool becomes a possibility despite the fact that a plurality of such pockets could be formed about the lowermost portion of the pool cover.
Applicant has developed a swimming pool cover which allows for the drainage of water and melting snow from the cover into the pool, while at the same time, preventing the passage therethrough of coarse waste, such as paper, leaves and branches. At the same time, Applicant's swimming pool cover provides for a filter media which would also trap the small particulate debris, such as dirt or decaying leaf particulate. Applicant's filter media would be positioned in a sleeve which would intersect the drain port of the swimming pool cover and be slidably positionable within the sleeve. The filter media would be sized in excess of the size of the drain port and would allow the pool owner to slidably position the filter media in alignment with the drain port. In this configuration, the pool owner is able to position virgin filter media in alignment with the drain port and to slidably move this filter media out of alignment when it becomes impregnated to the point where it prevents the flow of water or melting snow through the drain port. By slidably repositioning the filter media, the pool owner moves the impregnated, contaminated portion of the filter media out of alignment with the drain port and out of the sleeve where it can be cleaned and reinserted or substituted with a new filter or alternatively simultaneously move a virgin filter media into alignment with the drain port while moving the contaminated filter media out of alignment. This procedure could be performed several times during the course of a closed season, when the pool cover is in position thereby obviating the need for removal of the pool cover to clean the filter media while at the same time ensuring that no particulate matter enters the pool.